Abstract : The soil-moisture prediction method for U. S. soils was applied to sites located in the the Panama Canal Zone to determine whether the method was applicable for the prediction of moisture content of tropical soils. Factors necessary for the predictions were obtained at specific sites, and analysis of data shows that the method is applicable to Panama soils. Groundwater did not have an appreciable influence on soil-moisture depletion since drainage from the 0- to 12-in. layer was rapid. An analysis of strength data showed a highly significant relation between moisture content and cone index, and a lesser degree of significance between moisture content and rating cone index. No relation was found between moisture content and remolding index. On the basis of rating cone index, the trafficability of the residual soils was considered good. Trafficability of the alluvial marshland soils was considered good during the dry season and poor during the wet season.